Get rid of pg_class.reltoastidxid.

Treat TOAST index just the same as normal one and get the OID
of TOAST index from pg_index but not pg_class.reltoastidxid.
This change allows us to handle multiple TOAST indexes, and
which is required infrastructure for upcoming
REINDEX CONCURRENTLY feature.

Patch by Michael Paquier, reviewed by Andres Freund and me.

2 files changed, 37 insertions, 17 deletions

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index f23730c26f7..686770f881e 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -21,6 +21,7 @@
 #include "access/relscan.h"
 #include "access/rewriteheap.h"
 #include "access/transam.h"
+#include "access/tuptoaster.h"
 #include "access/xact.h"
 #include "catalog/catalog.h"
 #include "catalog/dependency.h"
@@ -1177,8 +1178,6 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 			swaptemp = relform1->reltoastrelid;
 			relform1->reltoastrelid = relform2->reltoastrelid;
 			relform2->reltoastrelid = swaptemp;
-
-			/* we should NOT swap reltoastidxid */
 		}
 	}
 	else
@@ -1398,18 +1397,30 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 
 	/*
 	 * If we're swapping two toast tables by content, do the same for their
-	 * indexes.
+	 * valid index. The swap can actually be safely done only if the relations
+	 * have indexes.
 	 */
 	if (swap_toast_by_content &&
-		relform1->reltoastidxid && relform2->reltoastidxid)
-		swap_relation_files(relform1->reltoastidxid,
-							relform2->reltoastidxid,
+		relform1->relkind == RELKIND_TOASTVALUE &&
+		relform2->relkind == RELKIND_TOASTVALUE)
+	{
+		Oid			toastIndex1, toastIndex2;
+
+		/* Get valid index for each relation */
+		toastIndex1 = toast_get_valid_index(r1,
+											AccessExclusiveLock);
+		toastIndex2 = toast_get_valid_index(r2,
+											AccessExclusiveLock);
+
+		swap_relation_files(toastIndex1,
+							toastIndex2,
 							target_is_pg_class,
 							swap_toast_by_content,
 							is_internal,
 							InvalidTransactionId,
 							InvalidMultiXactId,
 							mapped_tables);
+	}
 
 	/* Clean up. */
 	heap_freetuple(reltup1);
@@ -1533,14 +1544,12 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 		newrel = heap_open(OIDOldHeap, NoLock);
 		if (OidIsValid(newrel->rd_rel->reltoastrelid))
 		{
-			Relation	toastrel;
 			Oid			toastidx;
 			char		NewToastName[NAMEDATALEN];
 
-			toastrel = relation_open(newrel->rd_rel->reltoastrelid,
-									 AccessShareLock);
-			toastidx = toastrel->rd_rel->reltoastidxid;
-			relation_close(toastrel, AccessShareLock);
+			/* Get the associated valid index to be renamed */
+			toastidx = toast_get_valid_index(newrel->rd_rel->reltoastrelid,
+											 AccessShareLock);
 
 			/* rename the toast table ... */
 			snprintf(NewToastName, NAMEDATALEN, "pg_toast_%u",
@@ -1548,9 +1557,10 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 			RenameRelationInternal(newrel->rd_rel->reltoastrelid,
 								   NewToastName, true);
 
-			/* ... and its index too */
+			/* ... and its valid index too. */
 			snprintf(NewToastName, NAMEDATALEN, "pg_toast_%u_index",
 					 OIDOldHeap);
+
 			RenameRelationInternal(toastidx,
 								   NewToastName, true);
 		}
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 6a7aa44ccc6..6708725d696 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8878,7 +8878,6 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 	Relation	rel;
 	Oid			oldTableSpace;
 	Oid			reltoastrelid;
-	Oid			reltoastidxid;
 	Oid			newrelfilenode;
 	RelFileNode newrnode;
 	SMgrRelation dstrel;
@@ -8886,6 +8885,8 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 	HeapTuple	tuple;
 	Form_pg_class rd_rel;
 	ForkNumber	forkNum;
+	List	   *reltoastidxids = NIL;
+	ListCell   *lc;
 
 	/*
 	 * Need lock here in case we are recursing to toast table or index
@@ -8932,7 +8933,13 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 				 errmsg("cannot move temporary tables of other sessions")));
 
 	reltoastrelid = rel->rd_rel->reltoastrelid;
-	reltoastidxid = rel->rd_rel->reltoastidxid;
+	/* Fetch the list of indexes on toast relation if necessary */
+	if (OidIsValid(reltoastrelid))
+	{
+		Relation toastRel = relation_open(reltoastrelid, lockmode);
+		reltoastidxids = RelationGetIndexList(toastRel);
+		relation_close(toastRel, lockmode);
+	}
 
 	/* Get a modifiable copy of the relation's pg_class row */
 	pg_class = heap_open(RelationRelationId, RowExclusiveLock);
@@ -9010,11 +9017,14 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 	/* Make sure the reltablespace change is visible */
 	CommandCounterIncrement();
 
-	/* Move associated toast relation and/or index, too */
+	/* Move associated toast relation and/or indexes, too */
 	if (OidIsValid(reltoastrelid))
 		ATExecSetTableSpace(reltoastrelid, newTableSpace, lockmode);
-	if (OidIsValid(reltoastidxid))
-		ATExecSetTableSpace(reltoastidxid, newTableSpace, lockmode);
+	foreach(lc, reltoastidxids)
+		ATExecSetTableSpace(lfirst_oid(lc), newTableSpace, lockmode);
+
+	/* Clean up */
+	list_free(reltoastidxids);
 }
 
 /*